Eternal Mametchi Fan

This is weird... my P2 suddenly blanked out, and then showed the animation it usually shows when your Tama evolves. Then I had to set the time, so I guess it reset itself... It was the usual time Tamas sleep, and when I went to the main screen, it had a sleeping "Z" symbol... next to a UFO??? So I set the time to day time to see what would happen, and it wasn't a UFO anymore... it was an egg--a 5-year-old egg that weighed 20lb and could eat and play games! It never hatched... what on Earth happened???